I'm a proud and happy owner and user of a Yh-J70, it has served me wonderfully up until recently, despite the low battery life, which hasn't ever really been an issue for me.
A year ago I lost the ac charger for my J70. No big deal I thought, since i still have the usb cable I can charge it from the pc anytime. It all went well up until a month ago. After putting in a new folder i forgot to switch the device to "charge" upon connection to the pc, and i went on listening, silly me, until the battery expired.
Now I have no way whatsoever or charging it, connecting it to the computer gives me a "usb transfer" screen for like 2 seconds and then the player turns itself off (thought i still can hear the hard drive running). Is there a way to switch back to charge mode without being able to access the menu?